In general, examples of laundry treatment machines include washing machines that supply wash water into a drum holding laundry and remove contaminants from laundry and clothes and drying machines that supply hot air or cool air into a drum to dry laundry. Recently, laundry treatment machines that can perform a drying function as well as a washing function are being widely used.
The clothes drying machine is an apparatus that supplies hot air or cool air into a certain space or drum holding wet clothes to dry the wet clothes. Generally, the clothes drying machine includes a heater for generating heat and a blower for delivering the heat generated from the heater to the space holding clothes. The clothes drying machine induces evaporation of water by increasing the temperature of water contained in clothes using heat delivered by heated air. Since heat is transferred from air having a lower specific heat to water having a higher specific heat, the temperature of water does not significantly increase compared to the temperature of heated air, and the drying performance is low compared to the power consumption.
Also, since the air temperature inside the drum must be equal to or greater than 100 degrees Celsius in order for water contained in clothes to reach the evaporative temperature, contact of hot air with clothes may cause denaturalization or damage of cloth.
Furthermore, the drying machine may include an exhaust system for exhausting water evaporated from clothes out of the drying machine. In this case, since the internal temperature of the drum inevitably drops due to continuous exhaust of heated air, the operation time of the heater increases, and thus the power consumption and the drying time increase.